That's very strange. It sounds like Thunderbird is downloading messages automatically - and before Mailwasher does its regular interval check and "sees" and logs them ...
In Thunderbird, check Tools / Account Settings / Server Settings / and make sure that the <Automatically download new messages> is
unchecked. Make sure this is valid for the Thunderbird identity you are using - and indeed any others as well.
If that all passes as OK, drop a line to Nick at the Mailwasher support line.
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